Alpine field, Alaska: openhole completion and wellbore cleanup methods in an Artic environment

Abstract

This study compares the practices used to drill and complete three horizontal, openhole wells in the Alpine field on the north slope of Alaska. This study is a continuation of the work performed in conjunction with CEA-73. In the first phase of CEA-73, laboratory work was completed to study the most important parameters in drilling and completing openhole horizontal wells. This portion of the study applies the knowledge gained in the lab to field examples. It includes (1) a combination of previous laboratory work, (2) the monitoring of fieldwork where advanced well completion techniques have been applied, and (3) the performance analysis in wells where the techniques have been used. Through the analysis of well files (correspondence, personal interviews, test analyses, and other related data), the auditor studies the development of the well from the initial well plan through its production phase. The audit is designed to show if improved drilling and completion techniques result in more productive wells. The well audit reflected good planning throughout the Alpine horizontal well program. State of the art technology was considered, researched, and applied throughout the process. Using horizontal well decline type curve techniques, production data were studied to determine the degree of skin in each well. Results from the analysis indicate that there was a high level of impairment in the wells, indicated by the significant skin. It is suspected that despite good planning practices, the formation damage was caused by one or more factors, including: inadequate cleanup design, polymer degradation, and mud handling/carbonate sizing. Furthermore, the possibility of removing substantial amounts of this damage using the current methods is uncertain. Moderate remediation might be possible with altered cleanup practices.